1. Field of the Invention
The present invention is directed to an impact damper for deceleration of a vehicle upon impact on an obstacle by hydraulic damping forces and gas spring forces, the impact damper having at least two pipes which are telescopically displaceable one inside the other. The inner pipe of the two pipes is closed toward the outside by a base and has a gas space which is under pressure and which cooperates with a first liquid space through a dividing piston which is sealingly guided in the inner pipe. The first liquid space communicates with a second liquid space via a throttle opening located in an intermediate wall fastened in the inner pipe. An annular space is defined between the inner pipe and outer pipe and by a seal toward tile atmosphere and a seal by the intermediate wall.
2. Description of the Related Art
In known impact dampers such as, for example, the impact damper disclosed in U.S. Pat. No. 6,109,400, the deceleration of a vehicle upon impact on an obstacle is effected by hydraulic damping forces and gas spring forces. Two pipes are provided which are telescopically displaceable one inside the other. An inner pipe which is closed toward the outside by a base has a gas space under pressure which cooperates with a first liquid space through a dividing piston which is sealingly guided in the inner pipe. This first liquid space communicates hydraulically with a second liquid space via a throttle opening that is located in an intermediate wall fastened in the inner pipe, while a piston which is fastened to the piston rod is sealingly guided in the inner pipe and cooperates with a third work space. A control may be operatively joined to two chamber for extending the unit and for returning it to the normal position. The manner in which this control functions is not disclosed more fully in this reference.